Double drum winder

ABSTRACT

A method of and apparatus for controlling wound-in tension on a web winding machine wherein the web is wound on a web roll after passing through a first nip between a first drive drum and the web roll, about the web roll and through a second nip between a second drive drum and the web roll and then back through the first nip on a line between the first pass of the web through the first nip and the web roll. The nip pressure and the speed of the drive drum are controlled to produce a program on a record medium for controlling the tension in the same grade of web. During subsequent operational runs, the differential drum speed and the nip pressure are controlled to adjust the web tension as measured at a point between the second nip and the second path of the web through the first nip.

United States Patent 1191 1111 3,858,820

Crouse 1 Jan. 7, 1975 DOUBLE DRUM WINDER [5 7] ABSTRACT [75 Inventor; J w C B l i Wi A method of and apparatus for controlling wound-in l tension on a web winding machine wherein the web is [73] Asslgnee Balm Corporatmn, B610", wound on a web roll after passing through a first nip [22] Filed: Sept. 27, 1973 beta/veer; a fiirsthdrivehdrum andlthe web roll, about the we ro an t roug a secon nip between a second [211 Appl' 401,165 drive drum and the web roll and then back through the first nip on a line between the first pass of the web [52 U.S. Cl. 242/66, 242/75.51 through the first p and the web 1911- The p p 51 Int. Cl B65h 17/12 Sure and the speed of the drive drum are n ll d to [58] Field of Search 242/66, 73.51, DIG. l Produce a p gr m n a re rd medium for control- .ling the tension in the same grade of web. During sub- [56] References Cit d sequent operational runs, the differential drum speed UNITED STATES PATENTS and the nip pressure are controlled to adjust the web 3,599,889 8/1971 Pfeiffer 242/66 as measured a pom between the second 3,687,388 8/1972 Pfeiffer I h 242/65 and the second path of the web through the first mp. 3,730,450 5/1973 Hank 242/66 Primary Examiner-John W. Huckert Assistant Examiner-Edward J. McCarthy 9 Claims, 1 Drawing Figure Attorney, Agent, or Firm-Hill, Gross, Simpson, Van

Santen, Steadman, Chiara & Simpson 4040 CELL 46 44 4a e2 RECOQDtER CONTRQLL Q 42 DOUBLE DRUM WINDER BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to web winding techniques, and in particular to a method and apparatus for measuring and controlling the wound-in tension during the winding of a web on a roll and to automatically regulate nip pressure and drive drum speed to accordance with a predetermined operational program.

2. Description of the Prior Art D. C. Cronin in his U.S. Pat. No. 3,346,209 discloses a winder for controlling the compactness of a roll of sheet material in which a pair of winding drums drive a web roll utilizes a variable position rider roll forcontrolling the pressure in the nips between the winding drums and the web roll. A tensioning roll and/or a differential of air pressure may also be employed across the nips to control the compactness of the web roll.

John D. Pfeiffer, in his U.S. Pat. No. 3,687,388, also assigned to Beloit Corporation, discloses a web winding machine in which a pair of drive drums forms a pair of nips with a web roll. The web passes through the pair of nips and about a tension measuring roll of a load cell before being wound upon the web roll. A loading device is utilized to control nip pressure between the drive drums and the web roll in accordance with an optimum pressure schedule.

The coefficient of friction of paper for a paper to paper contact (pu is, in general, greater than the coefficient of friction of paper for a paper to steel contact 4,). Measurement of wound-in tension in a winding roll or web roll of paper is dependent on the paper to paper coefficient u The coefficient of friction is particularly important on the driving side of the web. If the driving side is a nip of paper on one side and steel on the other side, then slackness can occur giving inaccurate wound-in tension readings. In fact, it is possible that there may be no measurement at all of wound-in tension and the recording roll becomes nothing but a follower.

In both the aforementioned Cronin and Pfeiffer patents, the driving side is a nip of paper on one side and steel on the other side. The Pfeiffer technique tends to be more correct in that a capstan-type wrap is utilized prior to the nip to sustain driving the web by a paper to paper contact. Therefore, it is possible in the Pfeiffer arrangement to achieve a wound-in tension measurement. With such apparatus, however, this measurement may be lost as rider roll pressure is increased. Also, and as will be more particularly set forth below, the apparatus does not employ techniques for sensing the drum speed differential effects on wound-in tension.

SUMMARY OF THE INVENTION It is therefore a primary object of the invention to provide a new and improved method and apparatus for measuring and controlling wound-in tension on a web winding machine.

More specifically, it is an object of the invention to more accurately monitor and control wound-in tension in a web winding machine, particularly for winding paper, in which the wound-in tension is controlled as a function of the nip pressure and the drum speed differential on a double drum winder.

According to the invention, the'method and apparatus utilizes two drums for driving a web roll, a tension measuring roll and a rider roll. In general, as mentioned above, the wound-in tension is a function of the nip pressure (rider roll loading from the wound roll weight and the rider roll pressure) and the speed differential between the drive drums. The web traverses a path whichextends through a first nip between the first drive drum and the web roll, then about the web roll and through a second nip between the second drive drum and the web roll, then about a roll ofa tension measuring means and then again through the first nip between the web roll and the first pass of web through the first nip before actually being wound onto the web roll. A variable position rider roll is employed to change the loading at the nips in conjunction with the increasing weight of the web roll. With the tension measuring means located in a service loop between the second nip and the second pass of the web through the first nip, the combined effect of rider roll loading and speed differential between the two drums can be accurately sensed.

A winding program may be developed for any specific grade of paper for wound-in. tension vs. the com bined effect of rider roll loading and drum speed differential. These two variables may also be separated and separately utilized. A signal from the tension measuring roll may be fed into a recorder controller and signals from the rider roll loading apparatus and the drum speeds or speed differential may also be fed into the recorder controller. The program may be stored in accordance with any of a number of program storage techniques, such as magnetic tape, punched tape, etc; here, punched tape being utilized for purpose of illustration.

In the foregoing manner, a master program may be developed for a specific grade of paper and then utilized to control the wound-in tension from the signals BRIEF DESCRIPTION OF THE DRAWING Other objects, features and advantages of the invention, its organization, construction and operation will be best understood from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawing of a single FIGURE which illustrates, in schematic form, a method and apparatus for developing and utilizing a program for measuring and controlling wound-in tension on a two drum web winder in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, a web winder 10 is seen as comprising a pair of drive drums l2 and 16 which are independently driven at substantially the same speed by respective motors l4 and 18.

A web roll 20 is positioned in intimate contact with the drive drums l2 and 16 to form respective nips 24 and 26.

A tension measuring roll 28 is disposed below the drums l2 and 16 and the roll 20 to form a service or tension measuring loop in the web being wound on the web roll 20. A rider roll 30 forms a nip 32 with the web roll 20 and is utilized for changing the loading at the nips 24 and 26.

The drums and rolls are assumed to rotate in the directions indicated by the arrows and define a winding path for the web 22. This winding path takes the web 22 about the drive drum 12, a first pass through the nip 24, about the web roll 20 including passage through the nip 32, then through the nip 26, about the tension measuring roll 28, and then a second pass through the nip 24 before actual winding on the web roll 20.

lt is apparent from the foregoing that the double passage of the web through the nip 24 causes the second pass of the web to have a paper to paper contact with the drive drum 12, rather than a steel to paper contact and therefore be influenced by the greater coefficient u rather than the coefficient of friction n, which would be effective for a single pass steel to paper contact.

During a winding operation for a specific grade of paper, the wound-in tension may be monitored by way of a load cell 44 connected to the tension measuring roller 28 and fed to a recorder controller 42. Signals indicative of rider roll loading are also fed to the recorder controller 42 from a rider roller load sensing apparatus 38 by way of a signal channel 40. Signals indicative of drum speed may be developed by respective revolution counters 46 and 48 and fed to the recorder controller 42. As the optimum program is developed by varying the drive speeds and the nip load, the data received by the recorder controller 42 is fed by way of a data channel 50 to a tape punch/reader 52 which produces a punched tape 53 having the optimum program encoded therein in accordance with punched tape techniques.

During subsequent operational runs for winding the same grade of paper, the information 'stored in the punched tape 53 is read by the tape punch/reader 52 and fed to the recorder controller by way of an information channel 54. The recorder controller, in turn, controls the speed differential of the drums l2 and 16 by controlling the respective speeds of the drums by way of respective lines 60 and 62 to the drive motors l4 and 18. One skilled in the art will recognize that the control signals on the lines 60 and 62 actually operate respective speed control circuits for the motors l4 and 18. The nip load is either increased or decreased during winding by way of the signal channel 56 to apparatus 58 for controlling the nip pressure as the weight of the web roll 20 increases.

In summary, the wound-in tension may be accurately controlled in a double drum winder by utilizing the paper to paper coefficient of friction to advantage and by generating and utilizing an optimum winding program for any specific grade of paper.

Although I have described my invention by reference to a particular illustrative embodiment thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. I therefore intend to include within the patent warranted hereon all such changes and modifications as may reasonably and properly be included within the scope of my contribution to the art.

I claim:

l. A method of controlling wound-in tension on a web winding machine comprising the steps of: driving a web roll with a pair of other rolls to form respective nips between the rolls; passing a web through one ofthe nips, about the web roll, through the other nip, through the one nip again between the first pass through that nip and the web roll to form web-to-web contact at the one nip while simultaneously winding the web on the web roll; detecting the tension on the web at a point before the second pass through the one nip; and adjusting the web tension as a function of the detected tension.

2. A method of measuring and controlling the wound-in tension on a web winding machine, comprising the steps of:

driving a web roll into rotary motion with a pair of drums operated at substantially the same speed thereby forming a pair of nips between the drums and the web roll;

passing the web through one of the nips, about the web roll, through the other nip, then again through the one nip while simultaneously winding the web on the web roll to form web-to-web contact at said one nip;

measuring the web tension at a point between the other nip and the second pass of the web through the one nip;

comparing the measured web tension with a desired tension; and

adjusting web tension as a function of the difference between desired and measured tension.

3. The method of claim 2, comprising the steps of:

sensing the nip pressure;

sensing the difference in speed between the drums;

and

adjusting the nip pressure and the speed of each drum with respect to respective desired pressure and speeds.

4. The method of claim 3, comprising the steps of:

recording the adjusted tension, pressure and speed values; and

utilizing the record as a parameter control in subsequent winding operations.

5. A wound-in tension device for measuring and controlling wound-in tension of a web being wound on a roll,

comprising:

first and second driven winding drums spaced apart and each in intimate contact with the roll forming respective first and second nips;

tension measuring means including a tension measuring roll;

a rider roll in intimate contact with the winding roll forming a third nip and operated to urge the winding roll toward said driven drums as a function of measured tension; and

a web path extending through said first nip, about the winding roll through said third and second nips, about said tension measuring roll and through said first nip between the first pass of the web therethrough and the winding roll to form a web-to-web contact for the web as it is wound on the roll.

6. The device of claim 5, comprising:

means for storing operating data including the desired instantaneous speed of each drum, and the desired nip pressure;

means for measuring actual nip pressure;

means for measuring the actual speed of each drum;

means for comparing the measured values with the desired values; and

means for adjusting nip pressure and means for adjusting drum speed in accordance with the differences of the respective compared values.

7. The device of claim 5, wherein said tension measuring means includes a load cell connected to said tension measuring roll.

8. In a winding machine of the type wherein a web roll is driven by a pair of drive drums which form respective nips therewith and web tension is measured by apparatus including a tension measuring roll, the improvement therein comprising:

means defining a web-to-web contact at a first of the nips including a web path extending through the first nip, then about the web roll, then through the second of the nips, about the tension measuring roll, then again through the first nip between the first pass of the web therethrough and the web roll, and then onto the web roll.

9. A method of controlling wound-in tension on a web winding machine comprising the steps of: driving a web roll with a pair of other rolls to form respective nips between the rolls; passing a web through one ofthe nips, about the web roll, through the other nip, through the one nip again between the first pass through that nip and the web roll and then winding the web on the web roll; and adjusting the web tension in accordance with a predetermined web tension parameter. 

1. A method of controlling wound-in tension on a web winding machine comprising the steps of: driving a web roll with a pair of other rolls to form respective nips between the rolls; passing a web through one of the nips, about the web roll, through the other nip, through the one nip again between the first pass through that nip and the web roll to form web-to-web contact at the one nip while simultaneously winding the web on the web roll; detecting the tension on the web at a point before the second pass through the one nip; and adjusting the web tension as a function of the detected tension.
 2. A method of measuring and controlling the wound-in tension on a web winding machine, comprising the steps of: DRIVING a web roll into rotary motion with a pair of drums operated at substantially the same speed thereby forming a pair of nips between the drums and the web roll; passing the web through one of the nips, about the web roll, through the other nip, then again through the one nip while simultaneously winding the web on the web roll to form web-to-web contact at said one nip; measuring the web tension at a point between the other nip and the second pass of the web through the one nip; comparing the measured web tension with a desired tension; and adjusting web tension as a function of the difference between desired and measured tension.
 3. The method of claim 2, comprising the steps of: sensing the nip pressure; sensing the difference in speed between the drums; and adjusting the nip pressure and the speed of each drum with respect to respective desired pressure and speeds.
 4. The method of claim 3, comprising the steps of: recording the adjusted tension, pressure and speed values; and utilizing the record as a parameter control in subsequent winding operations.
 5. A wound-in tension device for measuring and controlling wound-in tension of a web being wound on a roll, comprising: first and second driven winding drums spaced apart and each in intimate contact with the roll forming respective first and second nips; tension measuring means including a tension measuring roll; a rider roll in intimate contact with the winding roll forming a third nip and operated to urge the winding roll toward said driven drums as a function of measured tension; and a web path extending through said first nip, about the winding roll through said third and second nips, about said tension measuring roll and through said first nip between the first pass of the web therethrough and the winding roll to form a web-to-web contact for the web as it is wound on the roll.
 6. The device of claim 5, comprising: means for storing operating data including the desired instantaneous speed of each drum, and the desired nip pressure; means for measuring actual nip pressure; means for measuring the actual speed of each drum; means for comparing the measured values with the desired values; and means for adjusting nip pressure and means for adjusting drum speed in accordance with the differences of the respective compared values.
 7. The device of claim 5, wherein said tension measuring means includes a load cell connected to said tension measuring roll.
 8. In a winding machine of the type wherein a web roll is driven by a pair of drive drums which form respective nips therewith and web tension is measured by apparatus including a tension measuring roll, the improvement therein comprising: means defining a web-to-web contact at a first of the nips including a web path extending through the first nip, then about the web roll, then through the second of the nips, about the tension measuring roll, then again through the first nip between the first pass of the web therethrough and the web roll, and then onto the web roll.
 9. A method of controlling wound-in tension on a web winding machine comprising the steps of: driving a web roll with a pair of other rolls to form respective nips between the rolls; passing a web through one of the nips, about the web roll, through the other nip, through the one nip again between the first pass through that nip and the web roll and then winding the web on the web roll; and adjusting the web tension in accordance with a predetermined web tension parameter. 